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Title: Metal-free syn-dihydroxylation of alkenes using malonoyl peroxides
Author: Rawling, Michael J.
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2013
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This thesis describes the successful application of cyclopropyl malonoyl peroxide II in the metal-free syn-dihydroxylation of alkenes I. Chapter 1 outlines the available metal-free methods for achieving syn-1,2- dioxygenation of alkenes. The use of hypervalent iodine, selenium, sulfur and peroxide reagents are discussed in terms of the advantages and limitations of each method. Chapter 2 details a mechanistic investigation into the dihydroxylation reaction using cyclopropyl malonoyl peroxide II. Through kinetic studies, Hammett analysis, multiple isotopic labelling experiments, NMR investigations and trapping experiments an ionic, stepwise mechanism has been proposed. Minor competing reaction pathways have also been identified in addition to an alternative reaction mechanism in the absence of water. Chapter 3 describes the current scope of the cyclopropyl malonoyl peroxide II mediated dihydroxylation reaction by alkene class. An application of the dihydroxylation protocol is presented in the stereoselective synthesis of a 5-deoxy-L-arabinose derivative. Interaction of cyclopropyl malonoyl peroxide II with non-alkene nucleophiles is also discussed, and a novel allylic oxidation protocol using peroxide II is introduced. Chapter 4 discusses catalysis of the dihydroxylation reaction. Alcoholic hydrogen-bond donors with a pKa of 5-8 were found to be the most effective catalysts, achieving up to 4-fold rate acceleration. Chiral hydrogen-bond catalysts are also investigated. Chapter 5 outlines the design, synthesis and reaction of chiral C2-symmetric malonoyl peroxides. The first enantioselective metal-free syn-dihydroxylation of alkenes using a peroxide reagent is reported. Chapter 6 presents preliminary investigations into a complementary antidihydroxylation protocol using cyclopropyl malonoyl peroxide II in anhydrous acetic acid.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral